Question: Which antinucleon quantum particle has the highest isospin quantum number?
Paraphrase: What is the highes isospin quantum number for an antinucleon particle?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q22675015 . ?ent wdt:P1126 ?obj . ?ent wdt:P279 wd:Q28855250 } ORDER BY DESC(?obj)LIMIT 5 
Answer: antiproton, antineutron